The present invention relates to an image forming apparatus, which makes it possible to insert cover papers and/or insertion papers, for indicating positions of divided sections, into recording mediums on which images are already formed, in a predetermined order.
Recently, according to the expansion of the information network proliferated with the development of a digitization technique, it has become possible to easily obtain a large amount of the digital image information digitalized in an overwhelming mass mode. These digital image information are not only employed for displaying images on the displaying device coupled to the personal computer, but also employed for forming images on the recording mediums. In addition, a number of the latter cases are getting increase recently.
Accordingly, there has been demanded for the image forming apparatus to efficiently form the images based on the obtained image information onto the recording medium within a short time. Specifically, when various kinds of post processing, such as, a staple processing, a punch processing, a fold processing, a stamp processing, etc., are applied to the recording mediums, which are accepted from the image forming apparatus and on which the images are already formed, the post processing apparatus is so constituted that a next bunch of paper sheets, as the next volume of the recording mediums, can be accepted immediately after the post processing apparatus enters into a processable state.
However, when applying the post processing mentioned in the above to plural volumes of the recording mediums, in addition to the processing time required for conducting the post processing, such as the staple processing, etc., the conveying time, for conveying the bunch of paper sheets of the recording mediums from the inside of the post processing apparatus into the ejecting tray of the post processing apparatus, is also required. As a result, the total processing time of the post processing apparatus has become longer that that of the image forming apparatus.
Accordingly, to cope with the above, the operations of the image forming apparatus should be temporarily deactivated until the post processing operations for the recording mediums are completed. There has been a problem that the abovementioned fact has deteriorated the productivity of the image forming apparatus.
To overcome the abovementioned drawback, for instance, Patent Document 1 sets forth the technology of the image forming apparatus in which the first conveyance path for conveying a first paper sheet and the second conveyance path for conveying a second paper sheet are provided in parallel and the stopper is equipped at each conveying path or at the merging point of the first conveyance path and the second conveyance path so as to match the leading edges of the first paper sheet and the second paper sheet with each other and to convey both of them in an overlapped state.
Further, for instance, Patent Document 2 sets forth the technology of the image forming apparatus in which the first paper sheet passes through the first conveyance path and is butted against the stopper disposed at the merged conveyance path so as to correct its skew, while the second paper sheet passes through the second conveyance path and is butted against the same stopper as the above so as to correct its skew as well, and when the two paper sheets overlap with each other, the stopper is opened so that the bunch of paper sheets are conveyed to the post processing section through the conveyance path, and then, ejected onto the stacker section after the post processing are applied to the bunch of paper sheets.
[Patent Document 1]                Tokkaihei 5-286619 (Japanese Non-Examined Patent Publication)        
[Patent Document 2]                Tokkaihei 10-250914 (Japanese Non-Examined Patent Publication)        
Since the image forming apparatus, set forth in Patent Document 1 or Patent Document 2, employs the two different conveyance paths for conveying the recording mediums, on each of which the image is already formed, to the post processing apparatus, the abovementioned method would be effective for such the case that the recording mediums, on each of which the image is already formed, are conveyed one by one to the post processing apparatus so as not to lower the productivity of the image forming apparatus.
However, when the bunch of paper sheets of the recording mediums is shaped in a booklet, or the like, sometimes, a recording medium for insertion use (an insertion recording medium), being different from the recording medium on which the image is to be formed, would be inserted as a cover sheet of the booklet or a delimiting sheet for indicating the change of the contents of the booklet in the post processing apparatus, instead of only conveying the recording mediums on which the images are already formed by the image forming apparatus.
Accordingly, since Patent Document 1 or Patent Document 2 describes no methods nor considerations in regard to the technology not to lower the productivity of the image forming apparatus even in the case that the abovementioned insertion recording medium is employed as the above, there has been a problem that the technologies set forth in Patent Document 1 or Patent Document 2 could not be applied to the image forming apparatus combined to the post processing apparatus.